Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / Os nanocompÃsitos a base de fosfatos de cÃlcio contribuem significativamente em tratamentos traumatolÃgicos, na cicatrizaÃÃo da estrutura Ãssea traumatizada, na regeneraÃÃo Ãssea e na reconstituiÃÃo Ãssea. Este trabalho teve como objetivo a produÃÃo de nanocompÃsitos a partir de pÃs de biocerÃmicas obtidas por precipitaÃÃo em soluÃÃo aquosa, reforÃados com diÃxido de silÃcio (SiO2). Os nanocompÃsitos foram produzidos em laboratÃrio com a adiÃÃo de sÃlica nanomÃtrica nas proporÃÃes de 15%, 35% e 50% em peso ao beta fosfato tricÃlcio nanomÃtrico. As amostras foram caracterizadas por difraÃÃo de raios-X, espectroscopia no infravermelho com transformada de Fourier (FTIR), microscopia eletrÃnica de varredura (MEV), espectroscopia de energia dispersiva de raios-x (EDX) e ensaio de resistÃncia mecÃnica por compressÃo diametral em amostras prensadas. Com os resultados de raios-X foi possÃvel identificar os picos representativos do beta fosfato tricÃlcio e observar que a intensidade dos picos diminui com o aumento da porcentagem de sÃlica nos nanocompÃsitos. Na anÃlise de FTIR foi possÃvel identificar os grupos presentes nos nanocompÃsitos. Os resultados obtidos na anÃlise de caracterizaÃÃo morfolÃgica apresentaram uma superfÃcie formada por partÃculas equiaxiais interligadas, e nÃo foi possÃvel verificar a dispersÃo das nanopartÃculas de sÃlica. Os ensaios de resistÃncia à traÃÃo por compressÃo diametral nas diferentes composiÃÃes de nanocompÃsitos mostraram que a porcentagem de sÃlica presente influencia na resistÃncia mecÃnica do material. / Calcium phosphate nanocomposites can be very useful in traumatologic treatments, for the healing of traumatized bone structure, for bone regeneration and bone reconstruction. This work aimed at the production of nanocomposites where a bioceramic matrix is reinforced with nanocrystalline silica (SiO2) particles. The matrix was produced from bioceramic nanopowders (beta tricalcium phosphate, β-TCP) obtained by precipitation in aqueous solution. The nanocomposites were produced in the laboratory by adding nanometric silica particles to the nanometric β-TCP in proportions 15%, 35% e 50% by weight. The material was characterized by x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and diametral compression testing of pressed disk samples. XRD results presented the characteristic peaks of β-TCP, which became less intense as the amount of silica particles increased. FTIR spectra allowed for the identification of groups present in the nanocomposites. SEM micrographs gave an idea of the microstructural of morphological aspects of the material, and showed that the surfaces consisted of a network of interconnected equiaxed particles. It was not possible to observe the dispersion of the silica particles. Diametral compression test results showed that the amount of silica influences the mechanical strength of the nanocomposite.

This diploma thesis deals with the preparation of modified tricalcium aluminate phases using sodium ions, and the study of their hydration processes and products. The X-ray diffraction analysis, isothermal calorimetry, laser diffraction, and scanning electron microscopy with energy dispersion analysis were used to solve this task. The preparation of modified tricalcium aluminate phases using high temperature methods has been described in the experimental section. Furthermore, the X-ray diffraction analysis was used to determine the purity of the prepared phases and the scanning electron microscopy with energy dispersion analysis was used to define the volume of sodium. Laser diffraction was used to measure a particle size distribution in the individual phases. Subsequently, hydration of the pure phases was performed in an isothermal calorimeter. It was followed by hydration of phases in the presence of different gypsum content and then in the presence of saturated portlandite solution. Hydration of some samples was stopped in order to better understand the hydration process. Hydration products were studied by X-ray diffraction analysis. The obtained results were compared with each other and the influence of sodium ions on both the structure of the prepared phases and the course of hydration and its products has been discussed. The effect of adding different volumes of gypsum and portlandite on the course of hydration of the individual phases was also compared.

Diplomová práce se zabývá přípravou trojrozměrných porézních kolagenových kompozitních nosičů pro tkáňové inženýrství kostí a studiem vlivu přídavku biokeramických částic na morfologické, biomechanické a biologické vlastnosti. Teoretická část popisuje biomateriály a biokeramické částice používané pro nosiče v tkáňové inženýrství kostí a jejich metody výroby. Pokud jde o experimentální část, byly vzorky připraveny metodou lyofilizace. Testovaným materiálem byl kolagen typu I z prasečího a hovězího zdroje, který byl kombinován s hydroxyapatitem a směsí -fosforečnanu vápenatého s -fosforečnanem vápenatým v poměrech 1 : 1, 1 : 2 a 2 : 1. Byl hodnocen vliv rozpustnosti a velikosti částic na morfologii, mechaniku a biokompatibilitu nosičů. Přidání biokeramických částic změnilo morfologii vzorků. Velikost pórů se snížila, zatímco pórovitost byla ve všech testovaných vzorcích téměř stejná. Biokeramické částice také způsobily, že kolagenová matrice nosičů byla méně hydrofilní, a navíc dokázaly stabilizovat nosiče proti působení enzymatické degradace. Biomechanické vlastnosti vzorků byly testovány v suchém i mokrém stavu. V suchém stavu dosáhl nejvyšší pevnosti v tlaku čistý bovinní kolagenový nosič, naopak v hydratovaném stavu, dosáhly nejvyšší hodnoty vzorky obsahující biokeramické částice. Žádný ze vzorků nebyl cytotoxický a nejvhodnější prostředí pro buněčnou adhezi a proliferaci bylo v čistém bovinním kolagenovém nosiči a také v kolagenovém kompozitním nosiči s poměrem HAp : -TCP : 1 : 1.

Tato diplomová práce je zaměřená na přípravu polymer-fosfátových kostních cementů. Cílem je optimalizovat antibakteriální vlastnosti daného cementu přídavkem selenových nanočástic (SeNPs). V teoretické části práce je popsána charakteristika kosti, vlastnosti fosforečnanu vápenatého (TCP) a jeho polymorfů, použití kostního cementu a antibakteriálních nanočástic v medicíně. Experimentální část se věnuje přípravě vzorků, popisu metod a vyhodnocení vlivu SeNPs na vytvrzování kostního cementu, morfologii, krystalinitu, mechanické, reologické a antibakteriální vlastnosti. Výsledkem je zvýšení injektovatelnosti cementu a zrychlení jeho vytvrzování včetně pozitivního vlivu na mechanické vlastnosti. Antibakteriální vlastnosti vzorků byly testovány použitím diskové i diluční metody, což vedlo k pozitivnímu inhibičnímu účinku SeNP na grampozitivních bakteriích (G+), zejména Staphylococcus aureus a methicillin rezistentní Staphylococcus aureus. Kvantitativní uvolňování SeNP z modifikovaného kostního polymer-fosfátového cementu umožňuje jeho použití jako antibakteriální kostní výplně (například pro léčbu zánětu kostí).

Orientador: João Manuel Marques Cordeiro / Abstract: The energetical and environmental problematic related to the cement production is a very sensitive issue. As every other field, the construction industry must go through drastic change in the design of concrete and cement-based materials. The understanding of the physical and chemical properties of the Portland cement (PC) clinker is important to improve its design. Tricalcium silicate C3S, or alite, is the main phase of PC clinker and has been largely studied since it is the first responsible for the strength development of the cement paste. On the other hand, the development of computational methods at the molecular scale has made possible the modelling of structural, dynamical and energetic properties, sometimes hardly measurable by experimental means. Such methods are relatively new in the field of cement chemistry, but have been increasingly employed over the last 15 years. In this project, density functional theory (DFT), classical molecular dynamics (MD), and ab initio molecular dynamics (AIMD) are employed towards a better understanding of mechanical, thermal, and superficial properties of monoclinic C3S, as well as C3S/water interface features. The present thesis consists of five chapters. The first chapter presents a review of the literature on the chemistry of cement, and more particularly on the hydration process modeling. The various phases which compose the Portland cement clinker are introduced, then the the different polymorphs of C3S are described, in particu... (Complete abstract click electronic access below) / Resumo: A produção de cimento envolve questões energéticas e ambientais muito relevantes. Em função disso, a indústria da construção deve sofrer mudanças radicais na concepção de concreto de materiais cimentícios. A compreensão das propriedades físicas e químicas do clínquer de cimento Portland (PC) é importante para melhorar seu design. O silicato tricálcico (C3S), ou alita, é a fase principal do clínquer de PC e tem sido amplamente estudado uma vez que é o principal responsável pelo desenvolvimento da resistência da pasta de cimento. Por outro lado, o desenvolvimento de métodos de cálculo na escala molecular possibilitou a modelagem de propriedades estruturais, dinâmicas e energéticas, às vezes difícil de medir por meios experimentais. Esses métodos são relativamente novos no campo da química do cimento, mas tem sido cada vez mais empregados nos últimos 15 anos anos. Neste trabalho, a teoria de funcional da densidade (DFT), a dinâmica molecular clássica (MD) e a dinâmica molecular ab initio (AIMD) são utilizadas para permitir uma melhor compreensão das características mecânicas, térmicas e de superfície do C3S monoclinico, bem como propriedades da interface C3S/água. Esta tese consiste em cinco capítulos: O primeiro capítulo apresenta uma revisão da literatura sobre a química dos cimento e, mais particularmente, sobre o processo de hidratação e sua modelagem. Introduzimos as diferentes fases que compõem o clínquer de cimento Portland, em seguida, a estrutura e os diferentes polimor... (Resumo completo, clicar acesso eletrônico abaixo) / Doutor

Calcium phosphate (CP) materials have been used extensively for bone replacement and augmentation due to their similarity to the mineral component of bone. In addition to being non-toxic, they are biocompatible, not recognized as foreign materials in vivo, and most importantly, exhibit osteoconductive behavior, being able to help in bone formation during healing. CPs form an intimate physicochemical bond with the host tissue, termed osseointegration. However the main limitation of calcium phosphates is their inherent brittle nature and poor mechanical performance under complex stress states. As a result, these materials have been used clinically only in non-load-bearing applications, primarily as granules. The primary goal of this research was to enhance mechanical performance of CPs, tricalcium phosphate (TCP) and hydroxyapatite (HAp) to be precise, in an attempt to develop controlled strength-loss resorbable/ bioactive ceramic bone-grafts for hard tissue engineering. In my work on TCP, I selected and introduced small quantities of single and multi-oxide sintering additives in TCP, to study their influence on sintering behavior, densification, mechanical properties and biodegradation/ biomechanical properties in vitro. Through this research, I could improve mechanical performance of [Beta]-tricalcium phosphate ([beta]-TCP) and controlled its rate of biodegradation by introducing of certain additives. In my second work, I improved mechanical performance of HAp (Ca10(PO4)6(OH)2 by reducing particle-size of the powder through the synthesis of stoichiometric, nanocrystalline, single phase HAp powder in the range of 2-20 nm. Synthesis of powder was accomplished via a modified low temperature sol-gel technique using ethanol/ water as solvent.

L’architecture des biomatériaux de comblement osseux à un réel impact sur l’activité cellulaire, la vascularisation et la diffusion de facteurs de croissance. Dans un premier temps, différentes membranes de polystyrène (PS) composées de fibres alignées ou aléatoires ont été étudiées. Elles sont non biodégradables et pourraient servir de supports pour la régénération de larges défauts osseux. Nous avons montré la cytocompatibilité in vitro des membranes en analysant l’adhésion, la prolifération et la différenciation cellulaire. Ensuite, des membranes de PS ont été enrichies de grains de β-TCP ou de nanoparticules d’or. Nous les avons implantées dans un modèle de défaut crânien de taille critique chez la souris. L’addition de β-TCP a stimulé la repousse osseuse grâce à la grande bioactivité des céramiques. Les membranes ont été biotolérées, les fibres ont été encapsulées dans l’os néoformé mais également dans un tissu conjonctif dense. Les nanoparticules d’or immobilisées sur des fibres ont migré dans l’os ou ont été phagocytées. Dans un second temps, différentes formulations de granules poreux de β-TCP ont été analysées par nanotomographie aux rayons X. L’architecture macroporeuse des granules varie inversement avec la concentration en β-TCP. Les faces internes montrent une grande hétérogénéité de minéralisation. Pour mimer les conditions d’utilisation en chirurgie maxillo-faciale, les granules ont été empilés dans des tubes. Nous avons montré que l’architecture des empilements de granules dépendait de leur forme. L’empilement de granules commerciaux (contenant12,5g de β-TCP) mime l’architecture naturelle et les propriétés physiques de l’os. / The architecture of bone filling biomaterials has a real impact on cellular activity, vascularization and diffusion of growth factors. As a first step, different polystyrene (PS) scaffolds composed of aligned or random fibers were studied. They were non-biodegradable and could be used as supports for regeneration of large bone defects. We showed the in vitro cytocompatibility of the scaffolds by analyzing cell adhesion, proliferation and differentiation. Then, polystyrene scaffolds were enriched with β-TCP grains or gold nanoparticles. We implanted them in a model of critical size defect in mouse calvaria. Addition of β-TCP stimulated bone regrowth due to the high bioactivity of the ceramics. Scaffolds were biotolerated, fibers were encapsulated in the newly formed bone and also in a dense connective tissue. The gold nanoparticles immobilized on fibers migrated into the bone or were phagocytized. As a second step, different formulations of porous granules of β-TCP were analyzed by X-ray nanotomography. The macroporous architecture of granules varies inversely with the concentration of β-TCP. The internal faces howed a great heterogeneity of mineralization. Tomimic the conditions in maxillofacial surgery, granules were stacked in tubes. We have shown that the architecture of the granules depends on their shape.The stacks of commercial granules (containing 12.5 g ofβ-TCP) mimicked the natural architecture and physical properties of bone.

Objetivo: o objetivo deste ensaio clínico controlado aleatorizado foi avaliar o uso de um substituto ósseo sintético associado a uma membrana de colágeno absorvível na preservação da crista óssea alveolar após extração dentária, por meio de análises clínica e tomográfica em humanos. Metodologia: Quatorze pacientes foram selecionados, cada um apresentando ao menos dois dentes anteriores maxilares indicados para extração: no Grupo Teste (GT), o alvéolo pós-exodontia foi preenchido pelo substituto ósseo sintético Reprobone, e no Grupo Controle (GC) houve o preenchimento do alvéolo apenas por coágulo. Em ambos os grupos os alvéolos foram cobertos por uma membrana absorvível de colágeno (BioMend), que por sua vez foi recoberta por um retalho mucoperióstico fechado oclusivamente. Tomografias computadorizadas do tipo Cone Beam foram realizadas no pós-operatório imediato e após 6 meses do procedimento cirúrgico, e as alterações dimensionais horizontais e verticais das cristas ósseas foram quantificadas. Para a análise estatística intragrupo utilizou-se o teste t pareado; para avaliações intergupo, teste t não pareado. Em todas as comparações foi adotado um nível de significância de 5%. Resultados: A Medida Vertical Vestibular reabsorveu 1,5 mm (ou 21,3%) da medida inicial no Grupo Teste (p<0,05) e 1,8 mm (ou 25,8%) no Grupo Controle (p<0,05). A Medida Vertical Palatina diminuiu 0,3 mm em ambos os grupos (p>0,05). A Altura Máxima reduziu 0,5 mm ou 7,9% no grupo com Reprobone e BioMend quando comparada ao baseline (p>0.05), e 1,1 mm ou 14,8% no grupo com BioMend apenas (p<0,05), sendo esta diferença intergrupo estatisticamente significante (p<0,05). A Medida Horizontal Apical diminuiu 0,2 mm no GT, o equivalente a 2,9% (p>0,05), enquanto que no GC diminuiu 0,5 mm ou 7,3% (p<0,05), não havendo diferença estatisticamente significante entre os grupos. A Medida Horizontal Cervical (MHC) perdeu 0,5 mm ou 7,2% no GT e 1,4 mm ou 15,1 % no GC: a análise intragrupo apontou diferença estatística entre os dados iniciais e após 6 meses para este parâmetro (p<0,05), em ambos os grupos, e também foi encontrada diferença estatisticamente significante na avaliação entre grupos para a MHC. Conclusão: Os resultados obtidos demonstraram que o uso do Reprobone associado à Biomend apresentou benefícios e melhores resultados na manutenção vertical e horizontal do rebordo alveolar em comparação ao uso apenas da membrana colágena. / Objective: The aim of this randomized controlled clinical trial was to evaluate the use of a synthetic bone substitute associated with an absorbable collagen membrane in preserving the alveolar crest after tooth extraction, through clinical and tomography analysis in humans. Methods: Fourteen patients were selected, each featuring at least two front teeth jaws indicated for extraction: in Test Group (TG), the post-extraction sockets were filled by the synthetic bone substitute ReproBone, and the control group (CG) was filling the alveoli only by clot. In both groups, the wells were covered with a resorbable collagen membrane (BioMend), which in turn was covered with a mucoperiosteal flap closed occlusally. CT Cone Beam type were performed in the immediate postoperative period and after 6 months of surgery, and the horizontal and vertical dimensional changes of the bone crests were quantified. For intra-group statistical analysis used the paired t test; to intergupo reviews, unpaired t test. In all comparisons was adopted a 5% significance level. Results: Vestibular Vertical Measure reabsorbed 1.5 mm (or 21.3%) of the original measure in the test group (p <0.05) and 1.8 mm (or 25.8%) in the control group (p <0 , 05). The Measured Vertical Palatine 0.3 mm decreased in both groups (p> 0.05). The Maximum Height reduced 0.5 mm or 7.9% for the ReproBone and BioMend compared to baseline (p> 0.05), and 1.1 mm or 14.8% for the BioMend only (p <0.05 ), statistically significant intergroup difference (p <0.05). Measure the horizontal apical decreased by 0.2 mm WG, equivalent to 2.9% (p> 0.05), whereas the CG 0.5 mm or decreased by 7.3% (p <0.05), not statistically significant difference between groups. The Horizontal Cervical Measure (MHC) lost 0.5 mm or 7.2% in GT and 1.4 mm or 15.1% of CG: the intra-group analysis showed statistical difference between the initial data and after 6 months for this parameter (p <0.05) in both groups, and was also a statistically significant difference between groups in the evaluation for the MHC. Conclusion: The results showed that the use of ReproBone associated with BioMend presented benefits and better results in vertical and horizontal maintenance of alveolar ridge compared to using only the collagen membrane.

Made available in DSpace on 2017-07-21T20:42:30Z (GMT). No. of bitstreams: 1 Conclusao.pdf: 46180 bytes, checksum: 47dccc8736224bc604a0ca46bd517b13 (MD5) Previous issue date: 2008-04-25 / Hydroxyapatite (HAP) samples were prepared by the chemical precipitation method and were added niobium phosphate (NbOPO4) through wet grinding, up to 1%, 5% and 10% in mass of NbOPO4. The samples were thermally treated under 1100°C and 1300°C. Analysis through X-ray powder diffractometry using the Rietveld method identified the phases in each sample. In vitro tests were conducted with HAP powders activated and non activated with NbOPO4. Analysis by scanning electron microscopy (SEM) allowed the observation of erythrocyte cell’s morphology after incubation of the samples with HAP and spectrometry on the visible region was used to measure the hemolytic index (H.I.) in these cells as well as the functionality of the intra cellular hemoglobin after exposition to the samples. In the samples thermally treated under 1300°C, calcium phosphate phases (a-TCP and b-TCP) were observed and for the thermal treatment up to 1100°C, non stequiometric hydroxyapatite, tricalcium phosphate (b-TCP), CaNb2O6 and Ca2Nb2O7 phases were detected. Increasing the NbOPO4 percentage produced enhancement in the quantities of tricalcium phosphate phases as well as in the unit cell volume of these samples. That result was observed at both temperatures of thermal treatment. There were no observable isolated peaks referring to the phases with Nb in the samples thermally treated under 1300°C; at 1100°C, the increase in the cell volume of the phase b-TCP was followed by um decrease of the cell volume of the phase Ca2Nb2O7. These effects suggest that the deformation observed in the cell parameters of the mentioned phases were caused by the entrance of the Nb ion in to the unit cell of these phases, under substitutional or interstitial conditions. The photomicrographs revealed changes of the erythrocytes morphology of cells incubated with the HAP samples. The results show that these samples do not have a significant hemolytic index (H.I.<2), getting slightly hemolytic to the percentage of 10% of NbOPO4 (10>H.I.>20) in a 0.8% hematocrit. There were no alteration in the functionality of the intra cellular hemoglobin (O2 transport), according to the reoxigenation tests under a controlled atmosphere, for hematocrit 0.8% and 40%. / Amostras de hidroxiapatita (HAP) foram obtidas pelo método da precipitação química e receberam adição de oxifosfato de nióbio (NbOPO4) por moagem úmida. As amostras aditivadas com 1%, 5% e 10% em massa de NbOPO4 foram tratadas termicamente a 1100°C e 1300°C. Análises de difratometria de raios X do pó utilizando o método de Rietveld identificaram as fases presentes em cada amostra. Foram conduzidos testes in vitro dos pós de HAP não aditivada e aditivada com NbOPO4. Análises por microscopia eletrônica de varredura (MEV) permitiram observar a morfologia eritrocitária pós-incubação com as amostras de HAP e a espectrometria na região do visível permitiu medir o índice hemolítico (I.H.) dessas amostras e a funcionalidade da hemoglobina intracelular face à exposição à droga. Com o tratamento térmico a 1300°C foram observadas fases de fosfato tricálcico (a- TCP e b-TCP) e com o tratamento a 1100°C fases de hidroxiapatita não estequiométrica, fosfatos de cálcio (b-TCP), CaNb2O6 e Ca2Nb2O7. Uma quantidade maior de NbOPO4 produziu aumento da quantidade das fases de fosfato tricálcico bem como no volume da cela unitária destas amostras. Esse resultado foi observado para ambas as temperaturas de tratamento térmico. Não foram observados picos isolados referentes a fases com Nb nas amostras tratadas termicamente a 1300°C; já a 1100°C o aumento do volume de cela da fase b-TCP foi acompanhado por decréscimo do volume de cela da fase Ca2Nb2O7. Esses efeitos sugerem que a deformação observada nos parâmetros da cela unitária das fases citadas foi causada pela entrada do íon Nb na cela unitária destas fases, em condição substitucional ou intersticial. As fotomicrografias mostraram alteração da morfologia eritrocitária para as células incubadas com as amostras de HAP. Os resultados mostraram que essas amostras não têm índice hemolítico significativo (I.H.<2), chegando a moderadamente hemolítico para a porcentagem de 10% de NbOPO4 (10>I.H.>20) em hematócrito de 0,8%. Não houve alteração na funcionalidade da hemoglobina intracelular quanto ao transporte de O2, conforme verificado nos testes de reoxigenação em atmosfera controlada para hematócritos de 0,8% e 40%.

Objetivo: o objetivo deste ensaio clínico controlado aleatorizado foi avaliar o uso de um substituto ósseo sintético associado a uma membrana de colágeno absorvível na preservação da crista óssea alveolar após extração dentária, por meio de análises clínica e tomográfica em humanos. Metodologia: Quatorze pacientes foram selecionados, cada um apresentando ao menos dois dentes anteriores maxilares indicados para extração: no Grupo Teste (GT), o alvéolo pós-exodontia foi preenchido pelo substituto ósseo sintético Reprobone, e no Grupo Controle (GC) houve o preenchimento do alvéolo apenas por coágulo. Em ambos os grupos os alvéolos foram cobertos por uma membrana absorvível de colágeno (BioMend), que por sua vez foi recoberta por um retalho mucoperióstico fechado oclusivamente. Tomografias computadorizadas do tipo Cone Beam foram realizadas no pós-operatório imediato e após 6 meses do procedimento cirúrgico, e as alterações dimensionais horizontais e verticais das cristas ósseas foram quantificadas. Para a análise estatística intragrupo utilizou-se o teste t pareado; para avaliações intergupo, teste t não pareado. Em todas as comparações foi adotado um nível de significância de 5%. Resultados: A Medida Vertical Vestibular reabsorveu 1,5 mm (ou 21,3%) da medida inicial no Grupo Teste (p<0,05) e 1,8 mm (ou 25,8%) no Grupo Controle (p<0,05). A Medida Vertical Palatina diminuiu 0,3 mm em ambos os grupos (p>0,05). A Altura Máxima reduziu 0,5 mm ou 7,9% no grupo com Reprobone e BioMend quando comparada ao baseline (p>0.05), e 1,1 mm ou 14,8% no grupo com BioMend apenas (p<0,05), sendo esta diferença intergrupo estatisticamente significante (p<0,05). A Medida Horizontal Apical diminuiu 0,2 mm no GT, o equivalente a 2,9% (p>0,05), enquanto que no GC diminuiu 0,5 mm ou 7,3% (p<0,05), não havendo diferença estatisticamente significante entre os grupos. A Medida Horizontal Cervical (MHC) perdeu 0,5 mm ou 7,2% no GT e 1,4 mm ou 15,1 % no GC: a análise intragrupo apontou diferença estatística entre os dados iniciais e após 6 meses para este parâmetro (p<0,05), em ambos os grupos, e também foi encontrada diferença estatisticamente significante na avaliação entre grupos para a MHC. Conclusão: Os resultados obtidos demonstraram que o uso do Reprobone associado à Biomend apresentou benefícios e melhores resultados na manutenção vertical e horizontal do rebordo alveolar em comparação ao uso apenas da membrana colágena. / Objective: The aim of this randomized controlled clinical trial was to evaluate the use of a synthetic bone substitute associated with an absorbable collagen membrane in preserving the alveolar crest after tooth extraction, through clinical and tomography analysis in humans. Methods: Fourteen patients were selected, each featuring at least two front teeth jaws indicated for extraction: in Test Group (TG), the post-extraction sockets were filled by the synthetic bone substitute ReproBone, and the control group (CG) was filling the alveoli only by clot. In both groups, the wells were covered with a resorbable collagen membrane (BioMend), which in turn was covered with a mucoperiosteal flap closed occlusally. CT Cone Beam type were performed in the immediate postoperative period and after 6 months of surgery, and the horizontal and vertical dimensional changes of the bone crests were quantified. For intra-group statistical analysis used the paired t test; to intergupo reviews, unpaired t test. In all comparisons was adopted a 5% significance level. Results: Vestibular Vertical Measure reabsorbed 1.5 mm (or 21.3%) of the original measure in the test group (p <0.05) and 1.8 mm (or 25.8%) in the control group (p <0 , 05). The Measured Vertical Palatine 0.3 mm decreased in both groups (p> 0.05). The Maximum Height reduced 0.5 mm or 7.9% for the ReproBone and BioMend compared to baseline (p> 0.05), and 1.1 mm or 14.8% for the BioMend only (p <0.05 ), statistically significant intergroup difference (p <0.05). Measure the horizontal apical decreased by 0.2 mm WG, equivalent to 2.9% (p> 0.05), whereas the CG 0.5 mm or decreased by 7.3% (p <0.05), not statistically significant difference between groups. The Horizontal Cervical Measure (MHC) lost 0.5 mm or 7.2% in GT and 1.4 mm or 15.1% of CG: the intra-group analysis showed statistical difference between the initial data and after 6 months for this parameter (p <0.05) in both groups, and was also a statistically significant difference between groups in the evaluation for the MHC. Conclusion: The results showed that the use of ReproBone associated with BioMend presented benefits and better results in vertical and horizontal maintenance of alveolar ridge compared to using only the collagen membrane.